The objectives of this application are: 1) To perfect a new kind of microtome invented by one of us (C.L. Krumdieck) for the purpose of preparing aseptic slices of live tissues for organ culture, and 2) To develop ancillary instrumentation for the rapid preparation of small square micro-slices of nearly identical dimensions suitable for cultivation in multi-well plates. The use of cultured organ explants, obtained by slicing live tissues to an optimal thickness that minimizes diffusion artifacts and maximizes the number of undamaged cells in the explant, has been limited by the unavailability of a suitable microtome. The method has, however, numerous actual and potential applications (e.g. in vitro toxicology, pharmacology, biochemistry, neurochemistry, neurophysiology and others) and offers a simple approach to reduce the number of experimental animals currently used in biomedical research. In addition, it offers the possibility of using human tissues (normal and/or neoplastic) obtained during surgery or ex cadaver for studies that avoid the need to extrapolate from animals to humans. Specifically, they propose to: 1) Fabricate and evaluate the performance of new prototypes of the Krumdieck microtome testing different materials and incorporating design improvements; and 2) Fabricate and evaluate a tissue-dicing instrument that, used in conjunction with the slicer, will permit the preparation of hundreds of micro-slices from small (approximately 1.0 cm") samples of tissue.